Monitoring of the Wines’ Quality by Gas Chromatography: HSS-GC/FID Method Development, Validation, Verification, for Analysis of Volatile Compounds

Abstract

One of the most common techniques for wine analysis is gas chromatography coupled with the flame ionization detector and headspace autosampler (HSS-GC/FID) for the analysis of the volatile compounds in the wine samples. The main goal of this thesis was to develop the method for the analysis of volatiles (methanol, higher alcohols, and esters) in wine samples made of Cabernet Sauvignon and Merlot. Validation parameters were: r2 > 0.995; LOD (0.2–1.0 mg/L); CV (2.7–6.3%), and recovery (92–106%). Average contents of the methanol (198.0 mg/L and 150.5 mg/L), higher alcohols (398.5 mg/L and 335.8 mg/L), ethyl acetate (42.0 mg/L and 55.6 mg/L), and acetaldehyde (23.3 mg/L and 16.1 mg/L) were determined for Merlot and Cabernet Sauvignon, respectively. Based on the obtained results, it was concluded that the content of methanol is in direct connection with the type of grape used for preparation of the wine. It was also found that the duration of the maceration directly influenced the content of the methanol and higher alcohols. On the other hand, type of grape appeared not to have influence on the content of ethyl acetate and acetaldehyde in wines. The post hoc Tukey’s HSD test at 95% confidence limit showed significant differences between observed samples. Principal Component Analysis (PCA) was used for assessing the effect of different genotypes and extraction methods on wine samples. Using PCA of observed samples, the possible directions for improving the quality of product can be realized.

Determination of Methanol, Acetaldehyde, and Ethyl Acetate in Thousand Folds of Ethanol Sample by Headspace Gas Chromatography with Mass Spectrometry

“…The results in Table 5 show the theoretical plates >2000, resolution >1.5, symmetry in the range 0.9–1.1, and the relative standard deviation of retention time <2%. These system suitability parameters were obtained as acceptance criteria from the International Conference on Harmonization (ICH) [ 20 , 21 ]. The method was suitable for the simultaneous analysis of ethanol, methanol, acetaldehyde, and ethyl acetate.…”

Volatilomics of Fruit Wines

“…Equipping the laboratory with an automatic SPME fibre extraction system coupled to a chromatograph (e.g., Gerstel) enables the significant acceleration of analyses and eliminates human error during determinations [ 162 ]. In order to enhance extraction efficiency, the addition of NaCl to the samples is a common practice [ 151 , 160 , 163 , 164 ]. In addition, internal standards are introduced into the vials prior to extraction.…”

“…Another technique is the introduction of the gas phase of the wine onto the gas chromatograph column. This is achieved by heating a vial (20 mL) containing a sample (1 mL) to 100 °C for 10 min, after which the volatile compounds are fed to the chromatograph column [ 164 ].…”

“…The flame ionisation detector (FID) is considerably less sensitive than mass detectors. In the case of isobutanol and isopropanol, the LOD ranged from 0.2 to 1.01 mg/L and the LOQ from 0.65 to 3.38 mg/L, respectively [ 164 ]. The detection of the analytes by mass spectrometry (single-quadrupole) yielded lower LOD and LOQ values than FID detection, with values of 0.004 and 0.02 mg/L, respectively [ 151 ].…”

Carbon-Isotope Ratio (δ13C) and Phenolic-Compounds Analysis in Authenticity Studies of Wines from Dealu Mare and Cotnari Regions (Romania)

“…Tukey's honest significance test is a single-step multiple comparison procedure for evaluation of statistical significance between multiple parameters of the evaluation of global variance for the same characterization (region or grape variety). In addition, for the discrimination by the variety according to the phenolic content and δ 13 C ratio, the discriminant function analysis test was applied using the same software [19].…”